A Little Filing here could save you a hole in the side of the engine. Some of the shift levers coming out of the factory have very sharp edges on the inside of the shifter.
And while the shift lever is off - check to make sure the clamping part of the shift lever, at the spline, has enough gap so when the bolt is tightened, there is still a gap - that way you know the shifter lever is firmly attached to the shifter shaft. Some shift levers come out of the factory without enough gap here to firmly grip, so the shifter stays on but after awhile it will get looser and may damage the splines before it is noticed. - Using a Dremel with a cut off wheel to grind off some material in the gap worked well for me.